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The present study undertaken in the largest coastal lagoon of Asia, Chilika, deals with monthly monitoring of benthic foraminifera assemblages in terms of distribution pattern, diversity and variations in taxonomic composition spanning over a period of 20 months. In total, 13 species of benthic foraminifera represented by eight families were identified in the lagoon. The stations in the Southern sector of the lagoon showed relatively low foraminifera abundance yet high diversity whereas higher abundance and lower diversity were observed in stations located in the Central sector which indicates the spatial patterning of the assemblage. Live foraminifera abundance was sparse in the study area indicating the stressed nature of the lagoon environment. The dissolved nutrient concentration of bottom water reflected significant seasonal variation. The stressed nature of the lagoon is further indicated by the dominance of the genus Ammonia across the inner sectors of the lagoon, a genus known to inhabit impacted habitats. Overall these data can serve as a baseline proxy for understanding palaeontological assemblages of foraminifera in similar shallow-water settings globally.

Crustacean decapod assemblages were surveyed in Zostera marina beds adjacent to tidal flats (ET) and rocky shore (ER), and in unvegetated habitats (UV). Decapod samples were collected monthly throughout 2002 using a small beam trawl from northern Jinhae Bay, Korea. Water temperature, salinity, eelgrass biomass, sediment composition and organic matter were also monitored to assess any correlation between environmental variables and decapod fauna. A total of 31 decapod species belonging to five taxa (three prawns, 13 caridean shrimps, one hermit crab, one mud shrimp and 13 crabs) were collected at three different habitats. To assess variations in decapod assemblages in relation to habitat type and season, various multivariate analyses were used. The dominant caridean shrimps were Palaemon macrodactylus, Alpheus digitalis and Crangon uritai, and the dominant crabs were Charybdis japonica, Hemigrapsus penicillatus and Charybdis bimaculata. The number, abundance and diversity of decapod species varied greatly with habitat type and season, peaking in eelgrass beds and during spring, and showing the lowest catch rate in unvegetated habitat and during winter months. The nMDS ordination and multivariate analyses revealed that habitat type and season were determinant factors affecting the structure of decapod assemblages. Seasonal shifts in the abundance of decapods corresponded with changes in eelgrass biomass and loss on ignition (LOI), but not with water temperature or salinity.

Despite the important ecological roles of commercial bêche-de-mer holothuroids in coral reef ecosystems their reproductive biology is poorly studied, including on the Great Barrier Reef (GBR). We investigated reproduction of Stichopus herrmanni, a commercially important species listed as Vulnerable, at One Tree Island, southern GBR. Gonad index, histology and spawning observations indicated an annual reproductive cycle with gamete release in the Austral spring and summer (November–February), as for populations of this species at a similar latitude in New Caledonia. Stichopus herrmanni releases gametes episodically, spawning multiple times during summer. Assimilation of spawning observations from OTI and elsewhere along the GBR and tropical Pacific revealed that gamete release by S. herrmanni is influenced by the lunar cycle, with spawning taking place around the new moon in summer. This species is an aggregative spawner with a behavioural change to attain elevated positions on the reef at dusk prior to spawning. After the spawning season, gametes remaining in the gonads are reabsorbed. Spent gonads completely lacked gametes. There was a quiescence in gonad development in winter with an absence of gonads in some specimens, indicating an aestivation-like period for reproduction. By late-winter (August) recovery stage gonads were distinguished by the initiation of gametogenesis, which coincided with increasing temperature and day length. Our findings contribute to the understanding of the reproductive biology of S. herrmanni, a consideration for future fisheries management in the protection of this Vulnerable species, especially with respect to the increasing global trade in bêche-de-mer.

Abalone (Haliotis spp.) are commercially important marine shellfish species worldwide. Knowledge about the physiology of abalone that impacts life-history traits is important for a better understanding of the biology of the species and the impact of stressful husbandry procedures at different seasons. The present study quantified the seasonal and diurnal variations in four physiological parameters of the European species Haliotis tuberculata, i.e. carbon aerial and aquatic respiration, calcification and excretion rates, and the effect of prolonged aerial exposure upon abalone aerial respiration. We also investigated the effect of individual size upon these physiological parameters. Aquatic respiration and calcification rates showed an allometric relationship with biomass. All parameters showed lower rates in cool season and higher rates in warmer season. Temperature was assumed to be the primary driver of the reported seasonal variability in physiological parameters, although reproductive needs and nutrition may also contribute to the observed patterns. Importantly, abalone did not stop calcifying in winter, and calcified more at night than during the day. Abalone did not respire more underwater at night-time than at daytime, however they excreted more overnight. The low air:aquatic ratio (0.2) is likely to be an energy-saving strategy for emerged H. tuberculata individuals. This study highlights the temporal heterogeneity in physiological rates of H. tuberculata, which constitutes a species recently domesticated in Europe.

Time-lapse photography was used to study the timing and duration of foraging activity of a population of the pulmonate gastropod Onchidella celtica on an exposed rocky shore in Cornwall, UK. The pulmonates spent most of their time in their home crevice, emerging onto open rock only during some ebb tides to forage for food and find a mate. Total duration and speed of foraging was highly variable and did not generally conform to a triphasic pattern. The number foraging was also highly variable and was not correlated significantly with the spring/neap tide cycle or weather (air temperature above 12°C, air pressure, solar radiation, precipitation, relative humidity and wind speed). There was a significant negative correlation between foraging and surf height. Although the pulmonates foraged during all hours of the day/night cycle, foraging activity tended to be highest during the afternoon and evening.

The abundance pattern and species diversity of phytoplankton in the surface waters of the Golden Horn Estuary were investigated between August 2011 and July 2012 in relation to environmental factors. Seventy-eight phytoplankton taxa (38 diatoms, 30 dinoflagellates and 10 phytoflagellates) belonging to eight taxonomic classes were identified in bottle and net samples. Phytoplankton abundance increased in spring and summer (from March to August) and reached its highest (10,429 × 103 cells L−1) during the bloom of Heterosigma akashiwo (Raphidophyceae) in the middle and upper estuary in late May. In general, phytoplankton abundance was higher in the middle estuary indicating more suitable conditions for phytoplankton growth, while species richness and diversity was higher in the lower estuary. The most abundant species were Skeletonema marinoi and Thalassiosira sp. among diatoms; Scrippsiella trochoidea among dinoflagellates; Plagioselmis prolonga and Heterosigma akashiwo among phytoflagellates. Diatoms were more abundant in the lower and middle estuary, while dinoflagellates and phytoflagellates in the upper estuary. The main factors causing the spatio-temporal variation of phytoplankton in the study area were temperature, salinity, water transparency and nutrients. Water transparency in the upper estuary is mostly influenced by organic and inorganic matter carried by two streams. As a result, this area should be considered a potential risk area for future algal blooms.

The genus Acanthogobius of gobiioid fish has been reported for six species from East Asia, and inhabits estuarine and coastal waters. Within this genus, Acanthogobius insularis is an endangered and endemic goby in the Amami-oshima and Okinawa-jima Islands, southern Japan, and its range is restricted to the lowermost course of a few river basins. Basic knowledge on this species is scarce in spite of its vulnerable conservation status. The purpose of this study was to elucidate the life history of A. insularis. Monthly sampling was conducted at five stations in the Taiho River, Okinawa-jima Island, from November 2014 to November 2015. Monthly standard length (SL) distributions were unimodal except in April during the recruiting period, suggesting that A. insularis is an annual species. Analysis of the gonadosomatic index and histological observations of the ovaries revealed that this species spawns from January to May. The beginning of the spawning season seems to be related to a decline in water temperature in December. Growth rates appeared to be lower from April to December and higher in winter months. From monthly collections, A. insularis was found to move upstream with growth, and gather at spawning grounds during the reproductive season. Acanthogobius insularis might be threatened by increasing water temperature due to climate change, since low water temperatures appear to be important for their reproduction and growth. Moreover, habitat diversity, from tidal flats for recruiting grounds to upstream sites with cobbles for spawning, is needed to complete their life cycle, and should be conserved.

Coastal environments are faced with constant habitat modification and biodiversity loss due to human occupation. Estuaries are considered to be highly productive and shelter heterogeneous habitats such as mangrove forests, tidal creeks, tidal mud flats and sandy beaches, which are important for the maintenance of natural resources. The present study aims to evaluate how different shallow juvenile habitats (sandy beaches, mangrove shoreline habitats and dense macrophyte habitats) influence fish during their early life stages in a tropical estuary of Brazil. Monthly samples using a beach seine net from July 2012 to June 2013 were collected in eight shallow areas of the São Mateus River estuary. The fish assemblage comprised mainly juvenile and small-sized fish, which included ecologically and commercially important species. Small recruits of Atherinella brasiliensis and Ctenogobius boleosoma were most abundant in the autumn, while Rhinosardinia bahiensis and Centropomus undecimalis were highly abundant during the winter. The water salinity recorded in the mid and lower estuarine portions was the most important variable for the distribution of A. brasiliensis and Sphoeroides spengleri, whereas Anchovia clupeoides, C. undecimalis, C. parallelus and Gobionellus oceanicus were positively correlated with the water depth of the upper estuarine portion. The fish species T. paulistanus, Genidens genidens and Achirus lineatus were related to the water turbidity in the upper portion. Thus, the heterogeneous shallow water habitats (and their associated environmental parameters) of the São Mateus River estuary are potential nursery grounds for the early life stages of a variety of fish species, which highlights the importance of these areas for local biodiversity management.

The shallow sandy marine subtidal ecosystem off Mar del Plata, Argentina, is the scene of multiple fisheries activities, in particular the prawn–shrimp Artemesia longinaris and Pleoticus muelleri grounds. We examined the δ13C vs δ15N isotope signatures of 22 species commonly found in the area in order to understand how this ecosystem supports the fishery, with special emphasis on imposex-affected gastropod populations. Our results indicate that the main food source for Olivancillaria urceus and Buccinanops monilifer were bivalves and crustaceans. Buccinanops duartei and Olivancillaria carcellesi feed on bivalves and also on macroalgae. These findings indicate, for the first time, a slight selectivity of some of the gastropods studied for local drifted algal sources and how gastropods may scavenge available food from by-catch returned to the sea. The fishes Urophysis brasiliensis and Callorhynchus callorhynchus appeared to be the top predators of this area with B. duartei and O. carcellesi constituting important components of their diet.

This study evaluated the population structure, growth and longevity of Xiphopenaeus kroyeri in the State of Sergipe. The obtained data were compared with other populations on a latitudinal scale in order to evaluate whether the latitudinal paradigm applies to this species. Shrimp sampling took place monthly from September 2013 to August 2014, in nine stations distributed at 5, 15 and 30 m depths, using a shrimp fishery boat equipped with a ‘double rig’ net. Sexual maturity was estimated by the logistic function y = a/(1 + b*exp(-cx)), and the sex ratio was analysed with the Chi-square test. The individual growth rate was estimated using the von Bertalanffy model, and the longevity was estimated by the inverse form of this formula. A total of 6418 (3457 females and 2961 males) was analysed. The size at onset of sexual maturity was 12 mm of carapace length (CL) for males and 12.5 mm CL for females. The total sex ratio did not differ from the expected (1:1). Males exhibited higher growth coefficients (k) and smaller asymptotic growth (CC∞ = 28.74 mm, k = 0.0081 day−1) than females (CC∞ = 30.79 mm, k = 0.0058 day−1). The estimated longevity (years) was 1.55 for males and 2.15 for females. No evident latitudinal pattern was observed regarding the size at onset of sexual maturity or the growth parameters for X. kroyeri. The information found, besides contributing to the knowledge about the biology of this shrimp, can also clarify hypotheses presented in relation to the latitudinal paradigm along the Brazilian coast.

Siphonophores are colonial hydrozoans that feed on zooplankton including fish larvae, and occur throughout the world's oceans from surface waters to ocean depths. Here we describe the composition of hyponeustonic siphonophores (0–3 m depth) from the tropical Colombian Pacific Ocean based on 131 plankton samples collected between June–October from 2001–2004. Samples were dominated by species of Calycophorae, with only three species of Physonectae identified, consistent with their deeper depth distribution. Muggiaea atlantica, Chelophyes contorta, Diphyes dispar, and Eudoxoides mitra were the most common of the 21 species identified. We found moderate structuring of the siphonophore community by the salinity gradient from inshore to offshore, and greater richness during the night because of diel vertical migration. Temperature did not play a significant role in structuring siphonophore communities, perhaps because of the narrow temperature range observed (3.5 °C). We extend the known temperature and salinity range of several species, including M. atlantica up to temperatures of 28.6 °C and salinities down to 24.7. Interestingly, only polygastric stages of M. atlantica were found, suggesting the reproductive stage of M. atlantica in tropical waters might be found in deeper waters. Chelophyes appendiculata was rare in our study and C. contorta was common, providing evidence they have a potential allopatric relationship, with C. contorta replacing C. appendiculata in warm water. Finally, we found siphonophore abundance was positively related to the abundance of copepods and fish eggs, with the top 13 most abundant species all having positive correlations, suggesting siphonophore abundances are tightly controlled by their food.

New Zealand rattail fish are of great interest both to biologists who study their phylogenetics and in fisheries. In contrast, their morphological evolution is little studied and poorly understood. Geometric morphometric methods based on scale shape were applied in this study to determine differences among species and genera. Scale shapes were described using seven landmarks, the coordinates of which were subjected to a generalized Procrustes analysis, followed by a principal components analysis. A cross-validated discriminant analysis was applied to assess and compare the size-shape (centroid size plus shape variables) efficacy in the species and the discrimination of the genera. Two main phenetic groups were identified: cluster no. 1 with eight species and cluster no. 2 with six species. Coelorhinchus aspercephalus and Mesovagus antipodum were more separated from the other species in the first cluster. The cross-validated canonical discriminant analysis correctly classified 74% at the genus level, with most misclassifications occurring between Coelorhinchus and Coryphaenoides, whereas the best classified genera were Mesovagus and Trachyrincus. The discrimination of correctly classified species ranged from 41.2 to 100%. The highest correct classification rates were recorded for Coryphaenoides armatus, Coelorhinchus innotabilis, Trachyrincus longirostris and Mesovagus antipodum.

Despite the prevalence of catch per unit effort (CPUE) as a key metric in fisheries assessments it can be fraught with inherent problems that often cause its use as an index of abundance to become contentious. This is particularly the case with abalone, a sedentary shellfish targeted by commercial dive fishers around the globe. It is common practice to standardize CPUE to at least partly address issues about how well it reflects the actual abundance of a stock. Differences between standardized and unstandardized trends may lead to controversy between scientists and stakeholders when standardized trends provide a less optimistic picture of stock status. It is within this context that we applied Linear Mixed Model (LMM) and Generalized Linear Mixed Model (GLMM) methods to standardize CPUE for the Western Zone blacklip abalone fishery in Victoria, Australia. This fishery was chosen for our evaluation because it included substantial population losses from a disease shock during the middle of the time series. The effects of diver, reef location, month and their interactions with year were included as random effects in these models and the results compared with nominal geometric means. The two standardization methods provided similar standardized CPUE trends and clearly demonstrated that a large proportion of the variance could be attributed to diver and spatial effects. The GLMM seemed to explain more variability in the data and produced better precision for standardized CPUEs than LMM. The temporal trend in variability attributed to divers and spatial scales reveals the impact of disease as well as any homo/heterogeneity effect. The CPUE trends responded to the impact of disease against a backdrop of declining stock, however when compared with the inter-annual pattern in nominal CPUE, the standardized trends showed that the decline immediately following the onset of disease was less precipitous. In contrast to what appeared to be an increase in the nominal series during the more recent post-disease period, there was only a slight non-significant increase observable in the standardized trends.

A study was conducted over eight consecutive days in February 2010 in which daily variations in the vertical distributions of heterotrophic bacteria, mesozooplankton and ichthyoplankton at 1–1200 m in the South-western Atlantic Ocean were investigated. Diurnal and nocturnal samples were collected at an oceanographic station at four regional depths: Tropical Water (TW) (1 m), South Atlantic Central Water (SACW) (250 m), Antarctic Intermediate Water (AAIW) (800 m) and Upper Circumpolar Deep Water (UCDW) (1200 m). Bacterial, mesozooplankton and larval fish densities significantly differed between sample depths but not between sampling tow times. In total, 154 zooplankton species and 18 larval fish species were identified. The highest number of taxa was obtained from the night-time TW trawls. This depth zone had the highest densities of mesozooplankton, larval fish and bacterioplankton (auto and heterotrophic), associated with the highest temperature and salinity and the lowest inorganic nutrient concentrations. Two sample groups were identified based on their mesozooplankton and larval fish compositions: night-time TW and other water masses (daytime TW, SACW, AAIW and UCDW). Thirty-two indicator species were detected in night-time TW. The copepod Nullosetigera impar was, to the best of our knowledge, identified for the first time on the Brazilian coast. Our results showed significant variability in the abundance and vertical distribution of mesozooplankton, bacterioplankton and larval fish along the water column in an oceanic area. We have provided new data and insights on the composition and vertical distribution of mesozooplankton, larval fish and bacterioplankton in deep waters in the South-western Atlantic Ocean.